1. Field of the Invention
The present invention relates to a nasally administrable composition containing a physiologically active peptide, and, more particularly, to a nasally administrable composition containing a physiologically active peptide such as peptide hormone, physiologically active protein, enzymatic protein and so on with a unique carrier, which is highly absorbable into the body via nasal route.
2. Description of the Prior Art
Physiologically active peptides such as calcitonin, insulin, parathyroid hormone (PTH), human growth hormone (HGH), gonadotropin-releasing hormone (GnRH) and derivatives thereof are polymers which are extensively employed in clinical practice for various medical usage owing to their specific physiological activity.
The physiologically active peptides, however, can little be absorbed intact from the mucous membrane of the intestine because of either being likely to be decomposed with proteases existing in the digestive system or being high in molecular weight and polarity. Hence, the administration method has been limited to injection. However, injection cannot be said to be preferable because it causes pain in patients. In particular, when injection is to be repeated at constant intervals, the patients have to suffer from the pain every time, which may often become too severe to endure. Under the circumstances, there has been strong demand for more simple and convenient means for administering physiologically active peptides, that is, administration via a non-injection route to enable patients to administer the drug by themselves.
As one example of preparations for such non-injection administration, an aerosol in the form of a suspension has been developed for nasal inhalation of calcitonin, in which a fluorinated hydrocarbon is used as a spouting agent. As another means for nasal administration, a spray has been proposed as a nasally administrable liquid preparation, which is a preparation in which calcitonin is formulated with a surface-active agent as an absorption promoter. Furthermore, recently, there have been proposed some nasally administrable powdery preparations with improved absorbability, which are prepared by adsorbing calcitonin onto a polysaccharide such as celluloses. These various techniques for nasal administration, which have recently been actively developed, are said to be in principle superior as a means for administering such physiologically active peptides as unlikely to be administered orally. Since venous plexus develops at the lamina propria mucosae of the nasal cavity, physiologically active peptides, when administered nasally, can be absorbed through the mucous membrane of the nasal cavity into the circulatory system of the body; however, nasally administrable preparations so far proposed cannot be sufficient because of poor absorbability of physiologically active peptides or local irritability, so that they are not commercially available yet.
The inventor of the present invention has actively been studying about carriers for nasal administration of physiologically active peptides such as insulin, calcitonin, parathyroid hormone (PTH), human growth hormone (HGH), gonadotropin-releasing hormone (GnRH) and so on, and has proposed nasally administrable compositions using a polyvalence metal compound such as hydroxyapatite and calcium carbonate as the carrier, finding that water-insoluble substances which are soluble under acidic condition, other than high molecular weight compounds such as polysaccharide celluloses so far studied, can be an desirable carrier for use in nasally administrable physiologically active peptide compositions.